The present invention relates to a tooling apparatus and especially to a quick change system for enabling cutting heads to be rapidly replaced on a rotary holder.
Quick change systems of the above-mentioned type have been heretofore in use. In one such system a master bar or holder comprises a front mounting face from which projects a frusto-conical tongue and a pair of reciprocable draw bolts. Front ends of the draw bolts carry enlargements, each of which can be coupled to recesses of a cutting head by a bayonet-type of connection in response to rotation of the cutting head. Rear ends of the draw bolts are attached to a bolt support which is axially rearwardly displaceable by means of a manually rotatable eccentric in order to move the draw bolts rearwardly. In that way, a frusto-conical socket of the cutting head can be pulled against the tongue of the holder. Rearward movement of the bolt support is performed against the action of a spring, whereby the spring functions to push the bolt support, draw bolts, and cutting head forwardly when the eccentric is rotated out of its tool clamping position. The bolt support is capable of free pivoting movement to enable the draw bolts to pull with equal force in order to ensure a true seating of the head.
With such an arrangement difficulties have been experienced in applying sufficient retraction force to the tool head by means of the draw bolts in order to prevent the tool head from chattering. Furthermore, the presence of the eccentric actuator makes it very difficult to provide a fluid passage in the apparatus for supplying flushing fluid to the tool head for flushing out the cuttings, as required in modern machines of this type.